New study is 'a leap forward' in our understanding of ice sheet behavior

February 17, 2016

The Antarctic ice sheet. Credit: Stephen Hudson / Wikipedia

In recent years, climate scientists have grown increasingly concerned that massive rivers of ice flowing into the ocean from Greenland and Antarctica could accelerate as the planet warms, leading to a catastrophic collapse of Earth's ice sheets.

This grim scenario would cause the world's oceans to rise rapidly, putting many island nations and coastal communities around the world under water.

But a new paper in Nature by C.R. Stokes and colleagues presents an alternative narrative of the manner in which an ice sheet can disappear, says Jason Briner, a University at Buffalo geologist who was not involved in the research.

The study will be published in Nature today, along with a Nature News and Views commentary by Briner discussing the implications of the research.

The Stokes paper examines the Laurentide Ice Sheet, which covered much of North America until about 10,000 years ago. The study presents a historical reconstruction of how ice streams behaved as the ice sheet disintegrated, and finds that ice loss through these frozen rivers did not increase rapidly as the ice sheet met its demise.

"Their evidence shows that ice streams turned on and off, and shifted from place to place, during the disappearance of the Laurentide Ice Sheet—the Antarctic-sized ice sheet that occupied Canada and the northern United States at that time," Briner writes in his Nature News and Views commentary. "Perhaps most notably, Stokes and colleagues find that ice-stream activity decreased as the planet warmed: the number of ice streams fell, the amount of ice expunged by them decreased and ice streams occupied a progressively smaller percentage of the ice-sheet edge."

The findings represent "a leap forward in our view of ice-stream activity on timescales longer than a few decades," writes Briner, PhD, an associate professor of geology in the UB College of Arts and Sciences.

He cautions, however, that this doesn't mean today's ice sheets will behave exactly as the Laurentide did. For one thing, the Laurentide Ice Sheet was quite different from the Greenland and Antarctic ice sheets, with one important difference that many of the Laurentide's ice streams terminated on land, while Greenland's and Antartica's flow into the ocean.

Despite these limitations, the Stokes study is an important piece of research because it provides a window into ice streams' complex behavior over long periods of time. As the Greenland and Antarctic ice sheets continue shrinking, they could become more similar to the Laurentide, with their rivers of ice eventually receding onto land, Briner says.

He adds that continued research on ice streams is extremely valuable because there is still a lot that scientists don't know about how these frozen rivers could shed ice and drive sea level rise as the planet warms.

"Greenland has three major ice streams—Jakobshavn, Kangerlussuaq and Helheim—and in the early 2000s, they all madly accelerated at the same time," Briner says. "So we had this doomsday scenario for a while, because if they continued to accelerate, their discharges into the ocean would be huge.

"Then, several years later, they slowed down again," Briner says. "There is still a lot we don't know about how these ice streams behave, and understanding their behavior is crucial for accurate modeling of future ice sheet decline."

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10 comments

Accepting the fact of imminent climate disaster it follows that there are two types of scientists, climate research scientists and useless scientists who waste funding that should be given to climate research. Non climate research scientists are selfish deniers of funding to climate research scientists who are trying to prevent extinction of the human race which would also eliminate any non climate science findings.

Non climate research scientists are selfish deniers of funding to climate research scientists who are trying to prevent extinction of the human race

@Philhyperbole much?

this is false... without fundamental research, ALL science is without a foundation

but even beyond that there is the fact that any research (regardless of discipline) may eventually tie together with other research, regardless of discipline. just because we can't see the connection now doesn't mean it might not be relevant later

case in point: people always talk about taking funding away from NASA because of the drain on the gov't funds that could be useful elsewhere... what they ignore is a whole lot from jobs to materials science to much much more

I have a friend who is a microbiologist. He tells me that the microbiology community is very concerned about antibacterial resistance. Some strains of TB are apparently looking very serious. Should we stop all funding to other science - due to the potential for a pandemic of TB?

I question the commitment of microbiologists and NASA scientists to the fight against global warming. In effect, by diverting funding from climate science research, these non essential scientists are deniers of the importance of global warming which, as we all know, will exterminate human civilization very soon thus erasing all microbiological and NASA scientific knowledge. Non climate research scientists are in effect terminating the human race which includes minority races, refugees, peaceful religious Muslims and our great leader in the fight against global warming disaster, president Obama.

I question the commitment of microbiologists and NASA scientists to the fight against global warming. In effect, by diverting funding from climate science research, these non essential scientists are deniers of the importance of global warming which, as we all know, will exterminate human civilization very soon thus erasing all microbiological and NASA scientific knowledge. Non climate research scientists are in effect terminating the human race which includes minority races, refugees, peaceful religious Muslims and our great leader in the fight against global warming disaster, president Obama.

I guess philstacy is advocating diverting all human resources to the study of climate change. No more military, welfare, social security, etc. etc. Just give it all to the climate scientists. Maybe phil is really that nutty, or maybe just being ironic - hard to tell which.

Funds diverted to non climate research only purchase the abortion of mankind's future. If we are serious about preventing climate disaster the useless scientists should be defunded and sent to the unemployment lines.

philstacy9 is also a little delusional......money funding non-climate research has not been "diverted". It was never earmarked for climate research to start with. There is also the fact that researching something to death may not at all be the best use of funds. Education and cultural change present much larger roadblocks to climate change action than lack of research.

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